Because Essential Faith is an all natural scent, each batch varies sightly due to time of harvest, amount of rainfall, length of season, etc.
The oil MUST be kept away from heat and sunlight as this can make it lose its potency.
Also, you may be experiencing what is known as "olfactory fatigue." This is when you become accustomed to a scent and although you may not be able to smell it, others around you still can.
Essential Faith is a very light scent, and works with one's body chemistry to create a different scent on everyone. The scent is most potent when used on the skin, and is harder to detect when smelling from the bottle directly. Apply desired amount and give it a few minutes to develop.
Lastly; any medications, allergies, or change in hormones can affect the scent on the wearer